At least to 100 mph, this pair is surprisingly well matched.

[UPDATE, September 26] Video has been removed from YouTube.

What separates a supercar from a hypercar? In the case of the McLaren Senna and 720S, the answer appears to be largely in the brakes. A new video from Autocar pits this British pair against each other on track. The first evaluation is to run them to 100 miles per hour (161 kilometers per hour) and back to a stop.

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There's bad news for Senna owners because it turns out that at legal speeds for most public roads that the 720S is quicker. According to this test, the Senna requires 1.75 seconds to reach 30 mph (48 kph) and 3.14 seconds 60 mph (97 kph). Conversely, the 720S needs just 1.6 seconds to hit 30 mph and 2.98 seconds to accelerate to 60 mph.

The situation narrowly switches at 100 mph because the Senna hits the speed in 5.4 seconds, and the 720S is a blink-of-a-second slower by needing 5.53 seconds. Still, 0.13 seconds is a scant difference considering the 720S goes for around $285,000, and the Senna trades hands for around $1 million.

Uh oh, a Senna crashed:

It turns out the Senna's bigger, motorsport-derived carbon-ceramic brakes are more potent than the ones on the 720S, though, that allows the hypercar to stop quicker than the supercar. Check out the clip above to find out just how big the difference is.

Autocar is also planning tests to time the pair of McLarens around a track and to decide which of them sounds better, which seems like quite a challenge. We suspect the Senna's bevy of aerodynamic aids should make the hypercar quicker around the circuit. Both vehicles have an amazing exhaust note, so a coin toss might be necessary to pick a winner.